The present invention generally relates to analyzing performance of a data processing system, and more particularly to analyzing input/output performance of a system.
Various performance characteristics of data processing systems are modeled to demonstrate the capabilities of different system configurations. For example, the number of instructions/second executed by the system may be particularly relevant for some applications, while the number of input/output operations/second may be of interest for other applications. Hardware and software vendors often use proprietary tools to model a system""s performance and project a performance increase when new hardware and/or software is added to the system.
In one example, Unisys Corporation uses a modeling tool to determine whether an outboard file cache, such as the Extended Processing Complex (XPC) product from Unisys, would enhance system performance. To use the model, the customer supplies a record of all input/output operations that occurred during a period of time for a present system. The record of input/output operations is then processed using the model to determine the performance level of the system with the addition of an outboard file cache.
As recognized by those skilled in the art, large scale data processing systems generally host different classes of workloads. For example, the 2200 Series data processing systems from Unisys support batch, demand, transaction, and background classes of workloads. Different input/output statistics have different levels of relevance for the different workloads. For example, the average response time can be calculated from the record of input/output operations. The response time statistic is of interest for demand and transaction workloads because there are typically users waiting for system responses. However, the response time statistic is of less relevance for batch and background workloads since these workloads don""t have end users waiting for responses.
Records of input/output operations are generally limited to process identifiers, word counts, and timestamps. Thus, modeling tools may be limited in the performance characteristics that can be reported. While a modeling tool may project a level of performance increase for an entire system, the tool may not provide any indication as to the performance increase for a particular class of workload. For example, the modeling tool may project an improved response time for the system, but provide no indication for demand workloads because the record of input/output operations has no indication of the workload class.
A method and apparatus that addresses the aforementioned problems, as well as other related problems, are therefore desirable.
A method for analyzing input/output performance of a data processing system is provided in various embodiments of the invention. In one embodiment, the method comprises providing records of input/output operations performed by the data processing system. Each record has statistics related to a respective input/output operation for a respective process. One or more workload classes are specified for accumulating statistics, and the statistics from the input/output records are accumulated by workload class. The accumulated statistics are reported by workload class which supports analysis of the input/output behavior for different workload classes.
In another embodiment, the method comprises providing records of input/output operations performed by the data processing system. Each record includes an operation-start timestamp, an operation-stop timestamp, an operation-type code, a data item count, and a device identifier. One or more workload classes are specified for the accumulation of input/output statistics, and the statistics are accumulated by workload class input/output from the records of input/output operations. The accumulated input/output statistics are then reported by workload class.
The above summary of the present invention is not intended to describe each disclosed embodiment of the present invention. The figures and detailed description that follow provide additional example embodiments and aspects of the present invention.